Oral administration of a substance, such as a drug or medicament, is frequently used, such as in the form of aerosol sprays for inhalation for the treatment of asthma. Another area of oral administration of a substance, such as a drug or medicament, is the area of nicotine-replacement therapy to give up smoking. Several apparatuses for the administration of nicotine containing aerosols have been described, such as in U.S. Pat. No. 5,810,018, U.S. Pat. No. 4,593,572 and U.S. Pat. No. 4,945,929.
One problem experienced with such medicaments being inhaled or administered locally in the oral cavity is the effects of substances having a disagreeable taste being distributed to the oral cavity of an individual. This is a problem in general with irritating and bad tasting drug substances and specifically a problem with nicotine. Such substances are influencing the taste and irritation sensory sites in the mouth and can cause problems when administered locally in the oral cavity to be absorbed through the oral mucosa. This is a particular problem when the drug is deposited on the back of the tongue where there is a high density of taste buds and in the upper throat where reflexes for nausea can be triggered.
When using traditional equipment for oral administration of an aerosol spray, a large part of the administered dose will end up in the whole oral cavity, the pharynx and/or the bronchial tree of the respiratory tract depending on the droplet size. Medicaments associated with inhalation, such as asthma drugs, are preferentially applied locally in the respiratory tract and lungs for a rapid and efficient effect. Still, not all orally sprayed medicaments are to be delivered to the respiratory tract and lungs, but are given locally in the oral cavity for uptake through the oral mucous membrane.
One such medicament is nicotine. Nicotine is an organic compound that is the principal alkaloid of tobacco. Nicotine is the chief addictive ingredient in the tobacco used in cigarettes, cigars, snuff and the like. Nicotine is also an addictive drug, though, and smokers characteristically display a strong tendency to relapse after having successfully stopped smoking for a time. Nicotine is the worlds second most used drug, after caffeine from coffee and tea.
The main problem with tobacco smoking is its enormous implications on health. Today it is estimated that smoking related diseases cause some 3-4 million deaths per year. This grim consequence of tobacco smoking has urged many medical associations and health authorities to take very strong actions against the use of tobacco.
Tobacco smoking can result in a dependence disorder. The WHO has in its International Classification of Disorders a diagnosis called Tobacco Dependence. Others like the American Psychiatric Association call the addiction Nicotine Dependence. Even though tobacco smoking is decreasing in many developed countries today it is hard to see how the societies could get rid of the worlds second most used drug.
Nicotine containing medications are currently the dominating treatments for tobacco dependence. There is also evidence of broader use of these medications like for smoking reduction and long term maintenance/substitution.
When smoking a cigarette, nicotine is quickly absorbed into the smoker's blood and reaches the brain within eight seconds after inhalation. The poisonous, toxic, carcinogenic, and addictive nature of smoking has provided efforts for methods, compositions and devices, which help in breaking the habit of smoking cigarettes.
For those who are unable to give up smoking there are several ways and forms of nicotine replacement products available on the market; such as nicotine gum. Several methods and means have been described for diminishing the desire of a subject to use tobacco, which comprises the step of administering to the subject nicotine or a derivative thereof as described in e.g. U.S. Pat. No. 5,939,100, U.S. Pat. No. 4,967,773, U.S. Pat. No. 865,026, U.S. Pat. No. 940,521. Aerosol compositions are described in GB 1 528 391, GB 2 030 862, U.S. Pat. No. 5,810,018, EP 0 557 129 and U.S. Pat. No. 4,593,572 and are adapted to be sprayed into the mouth of the user. Also, inhaling devices resembling a cigarette are known for ingestion of nicotine vapours orally as suggested in U.S. Pat. No. 5,167,242. Finally, ways of administrating nicotine is by way of delivering directly into the nasal cavity is known from U.S. Pat. No. 4,579,858, DE 32 41 437 and WO/93 127 64. Said means and methods address the problems associated with addiction to nicotine.
However, as stated above, a major drawback with the presently available nicotine containing aerosol spray devices is the fact that they deliver a large part of the dose in the back of the mouth cavity. This generally results in an experience of a bad and disagreeable taste, nausea and other irritations.
Several proposals have been provided for solving said problem of bad and disagreeable taste. Flavourants, such as tobacco flavouring, menthol or methyl salicylate, for example, may be added to impregnate such nicotine taste to produce an oral nicotine spray with a pharmacologically acceptable flavour. U.S. Pat. No. 4,967,773 describes the addition of liquorice, cocoa, aniseed and peppermint to a nicotine lozenge to avoid the bad taste of nicotine.
Still, none of the above mentioned means and methods addresses the problems associated with the bad taste of nicotine in any other way but addition of different flavouring agents.
Even though flavouring to conceal the bad taste of a medicament may partly circumvent the problem of bad tasting drugs it includes the further step in the production of the medicament of adding the desired flavouring agent. Moreover, addition of a flavourant may not conceal the taste or the irritating effect very well or long enough.
WO 95/20 411 describes a method of converting a medicament to a form usable for administration of the medicament to the airways or respiratory tracts of mammals. This is to bring the medicament to the location where it will do most good on people suffering from respiratory problems, such as asthma.
WO 99/6550 describes an inhalation device for providing pulmonary medicament for inhalation where the inhalation device includes a vortex generator. The vortex created through this vortex generator gives the smoker a feeling of “mouthfulness” close to what is experienced when smoking a cigarette.
GB 2 308 992 A describes a nebulizer for administering an aerosol to the lungs of patients requiring respiratory therapy, by producing a large number of small droplets and fewer large droplets in the aerosol produced by the nebulizer.
All said devices for oral administration describe means and methods for specific local delivery into the respiratory tracts, where the aim is to avoid as much as possible of the aerosol to deposit in the oral cavity.
Thus, there is a need for a delivery system, which solves the above mentioned problems associated with oral administration of substances, such as drugs and medicaments, having a bad, irritating or otherwise disagreeable taste and at the same time achieve an efficient medication, i.e. an efficient blood concentration of the substance.